ABSTRACT: Herbicide promotes physiological and biochemical changes even in tolerant species. The objective of this study was to evaluate the interference of the herbicides clodinafop-propargyl and 2,4-D in the antioxidant system of wheat, and iodosulfuron-methyl in wheat and ryegrass. Two studies, divided into three experiments, were conducted in an entirely randomized design in a greenhouse and phytotron. The first study tested herbicides iodosulfuron-methyl, clodinafop-propargyl, 2,4-D, and a control without application in wheat. The second, divided into two experiments with wheat and ryegrass, tested iodosulfuron-methyl doses (0, 1.75, 3.5, and 7.0 g a.i. ha-1). The variables analyzed were the concentrations of chlorophylls a, b, carotenoids, hydrogen peroxide (H2O2), lipid peroxidation (TBARS), electrolyte leakage, and antioxidant system activity. The herbicide treatments iodosulfuron-methyl, clodinafop-propargyl, and 2,4-D decreased the concentrations of chlorophylls and carotenoids in wheat plants. The herbicides promoted oxidative stress with increased H2O2 and TBARS concentrations. Increasing the dose of iodosulfuron-methyl provided a reduction in the activity of the enzymatic antioxidant system in wheat and ryegrass. ABSTRACT species clodinafoppropargyl clodinafop propargyl 2,4D 24D D 2,4 2 4 iodosulfuronmethyl iodosulfuron methyl ryegrass studies phytotron iodosulfuronmethyl, methyl, clodinafoppropargyl, propargyl, 2,4D, D, second 0, 0 (0 175 1 75 1.75 35 3 5 3.5 70 7 7. ai i a.i ha1. ha1 ha . ha-1) b H2O2, HO , H O (H2O2) TBARS, (TBARS) leakage plants H2O 4D 24 2, ( 17 1.7 3. ha-1 (H2O2 (TBARS 1. ha- (H2O

RESUMO: A aplicação de herbicidas promove alterações fisiológicas e bioquímicas mesmo nas espécies tolerantes. O objetivo do estudo foi avaliar a interferência dos herbicidas clodinafop-propargyl e 2,4-D no sistema antioxidante do trigo, e iodosulfuron-methyl em trigo e azevém. Dois estudos, divididos em três experimentos, foram conduzidos em delineamento inteiramente casualizado em casa de vegetação e fitotron. O primeiro estudo testou os herbicidas iodosulfuron-methyl, clodinafop-propargyl, 2,4-D, e testemunha sem aplicação em trigo. O segundo, dividido em dois experimentos com trigo e azevém, testou doses de iodosulfuron-methyl doses (0, 1,75, 3,5, and 7,0 g i.a. ha-1). As variáveis analisadas foram as concentrações de clorofilas a, b, carotenoides, peróxido de hidrogênio (H2O2), peroxidação lipídica (TBARS), extravazamento de eletrólitos e atividade do sistema antioxidante. O uso dos herbicidas iodosulfuron-methyl, clodinafop-propagyl e 2,4-D diminuíram o teor de clorofilas e carotenoides nas plantas de trigo. Os herbicidas promovem estresse oxidativo com aumento no teor de H2O2, TBARS e extravasamento de eletrólitos. O aumento da dose do iodosulfuron-methyl proporciona redução da atividade do sistema antioxidante enzimático no trigo e azevém. RESUMO tolerantes clodinafoppropargyl clodinafop propargyl 2,4D 24D D 2,4 2 4 iodosulfuronmethyl iodosulfuron methyl azevém estudos fitotron iodosulfuronmethyl, methyl, clodinafoppropargyl, propargyl, 2,4D, D, segundo 0, 0 (0 175 1 75 1,75 35 3 5 3,5 70 7 7, ia i i.a ha1. ha1 ha . ha-1) b H2O2 HO , H (H2O2) TBARS, (TBARS) clodinafoppropagyl propagyl 4D 24 2, ( 17 1,7 3, ha-1 H2O (H2O2 (TBARS 1, ha- (H2O

RESUMO: A qualidade da água é uma das principais características para uma aplicação eficiente e segura de pesticidas. De maneira geral, a qualidade da água está relacionada aos níveis de pH e dureza. Assim, o objetivo foi avaliar a interação entre o pH da água e tempo de mistura da calda contendo os herbicidas 2,4-D amina, 2,4-D colina e dicamba, na eficácia visível em Ipomoea triloba, Bidens pilosa, Amaranthus viridis; além dos níveis de dureza da água em I. triloba. Três estudos feitos em estufa. Estudo 1 em fatorial 3x5 sendo o fator A pH de 2, 6 e 10 e o fator B 0, 2, 6, 24 e 26 horas da mistura até a aplicação. Estudo 2 em fatorial 3x5 para cada herbicida, sendo o fator A pH de 2, 6 e 10 e o fator B 0, 6, 12, 24 e 48 horas da mistura até a aplicação. Estudo 3 em fatorial 3x7 sendo o fator A os herbicidas e o fator B níveis de dureza da água: 0, 65, 125, 250, 500, 750 e 1000 partes por milhão. O pH manteve-se estável nas 48 horas. Entretanto, não interferiu na eficácia de dicamba em I. triloba. Além disso, maior tempo entre o preparo da calda com as formulações de 2,4-D e a aplicação causou redução da eficácia em I. triloba. Ainda, a dureza da água diminuiu o controle sobre I. triloba. O pH não afetou 2,4-D e dicamba sobre as plantas, entretanto, maior tempo de aplicação reduz a eficácia. RESUMO pesticidas geral Assim 2,4D 24D D 2,4 4 amina triloba pilosa viridis I estufa x 3x 0 herbicida 12 65 125 250 500 75 100 milhão mantevese manteve se Entretanto disso Ainda plantas entretanto 4D 25 50 7 5

ABSTRACT: Carrier water quality is one of the main characteristics for an efficient and safe spraying of pesticides. Overall related to the levels of pH and hardness. The objective was to evaluate the interaction between water pH and storage time of the spray, containing 2,4-D amine, 2,4-D choline and dicamba, on the visible efficacy in Ipomoea triloba, Bidens pilosa, Amaranthus viridis; and water hardness on I. triloba. Three studies were carried out in a greenhouse. Study 1 with a 3x5 factorial, which factor A being pH of 2, 6 and 10 and factor B being 0, 2, 6, 24 and 36 hours of application after the mixture. Study 2 was a 3x5 factorial for each herbicide, whith factor A being the levels of pH (2, 6 and 10) and factor B being 0, 6, 12, 24 and 48 hours of application after the mixture. The study 3 is a 3x7 factorial, with factor A being the herbicides and factor B levels of water hardness: 0, 65, 125, 250, 500, 750 and 1000 parts per million. The pH of all solutions remained stable for 48 hours after preparation. However, did not interfere in efficacy of dicamba in I. triloba. Also, longer time between preparing the spray with 2,4-D formulations and application caused reduction efficacy on I. triloba. Also, the level of water hardness decreased control on I. triloba. The pH of carrier water did not affect efficacy of 2,4-D and dicamba on the weeds; however, longer time of the spray application reduce the visible efficacy. ABSTRACT pesticides 2,4D 24D D 2,4 4 amine triloba pilosa viridis I greenhouse x 3x 0 mixture herbicide (2 12 65 125 250 500 75 100 million preparation However Also weeds however 4D ( 25 50 7 5

ABSTRACT: Italian ryegrass (Lolium multiflorum Lam.) is considered one of the main winter cover crops in southern Brazil; however, it is a weed species with a record of being resistant to several herbicides. The settlement of this species in agricultural areas occurs through the seed bank in the soil, and measures that interfere with seed production can assist in its management. The present study evaluated the phytotoxicity, production, and quality of Italian ryegrass seeds through the application of herbicides 2,4-D and saflufenacil at different stages of development. Three trials were conducted, a completely randomized experimental design for the first two and randomized blocks for the third, all with four replications. The treatments were arranged in a 3x3 factorial scheme, in which factor A was composed of the herbicides saflufenacil (35 g a.i. ha-1), 2,4-D (1005 g a.e. ha-1), plus control without application; and factor B consisted of the booting, anthesis, and maturation Italian ryegrass development stages. The phytotoxicity of the herbicides to Italian ryegrass did not exceed 30%, with saflufenacil causing the greatest injury at anthesis. There was a reduction in Italian ryegrass seed yield when herbicides 2,4-D and saflufenacil were applied, and the application of 2,4-D and saflufenacil at anthesis reduced the percentage of full seeds. The number of empty Italian ryegrass seeds was higher when saflufenacil was applied at anthesis. The application of 2,4-D at maturity reduced Italian ryegrass germination and radicle length. From this perspective, these herbicides can help reduce the production and quality of Italian ryegrass seeds. ABSTRACT Lolium Lam. Lam Brazil however soil management 2,4D 24D D 2,4 2 4 conducted third replications x 3x scheme 35 (3 ai i a.i ha1, ha1 ha 1 , ha-1) 1005 (100 ae e a.e booting 30 30% length perspective 4D 24 2, 3 ( ha-1 100 (10 ha- 10 (1

RESUMO: O azevém (Lolium multiflorum Lam.) é considerado uma das principais plantas de cobertura hibernais do sul do Brasil, porém é uma espécie daninha com registro de resistência a diversos herbicidas. O estabelecimento dessa espécie nas áreas agrícolas ocorre através do banco de sementes no solo, sendo que medidas que interfiram na produção de sementes podem auxiliar no seu manejo. O objetivo do presente trabalho foi avaliar a fitotoxicidade, produção e qualidade de sementes de azevém mediante aplicação dos herbicidas 2,4-D e saflufenacil em diferentes estádios de desenvolvimento. Foram realizados três estudos, em delineamento experimental inteiramente casualizado para os dois primeiros, e blocos casualizados para o terceiro, todos com quatro repetições. Os tratamentos foram arranjados em esquema fatorial 3x3, em que o fator A foi composto pelos herbicidas saflufenacil (35 g i.a. ha-1), 2,4-D (1005 g e.a. ha-1), mais testemunha sem aplicação; e o fator B constituiu-se dos estádios de desenvolvimento do azevém emborrachamento, antese e maturação. A fitotoxicidade dos herbicidas ao azevém não superou 30%, sendo que o saflufenacil promoveu maior injúria e no estádio de antese. Ocorreu redução na produtividade de sementes de azevém quando recebeu aplicação dos herbicidas 2,4-D e saflufenacil, sendo que a aplicação em antese de 2,4-D e de saflufenacil reduz o percentual de sementes cheias. O número de sementes vazias de azevém foi maior quando foi aplicado saflufenacil no estádio de antese. A aplicação de 2,4-D em maturação reduziu a germinação e comprimento da radícula de azevém. Nessa perspectiva, estes herbicidas podem auxiliar na redução da produção e qualidade de sementes de azevém. RESUMO Lolium Lam. Lam Brasil solo manejo 2,4D 24D D 2,4 2 4 estudos primeiros terceiro repetições 3x3 x 35 (3 ia i i.a ha1, ha1 ha 1 , ha-1) 1005 (100 ea e.a constituiuse constituiu se emborrachamento 30 30% cheias perspectiva 4D 24 2, 3x 3 ( ha-1 100 (10 ha- 10 (1

ABSTRACT The cultivation of pecan (Carya illinoinensis K. Koch) and olive trees (Olea europaea L.) near pasture and grain cultivation areas in southern Brazil has caused herbicide drift problems. Therefore, the objective of this study was to evaluate the phytotoxic effects of herbicides 2,4-D and dicamba on the growth of pecan and olive tree seedlings. A total of 8 underdoses were used, as follows: 0, 1.56, 3.125, 6.25, 12.0, 25.0, 50.0, and 100% of the recommended doses of herbicides 2,4-D (670 g a.e ha-1) and dicamba (720 g a.e ha-1) for burndown. The applications were carried out in 80 cm-high seedlings with the aid of a CO2 pressurized sprayer with a spray solution volume of 150 L. ha-1. The analyzed variables were phytotoxicity at 7, 14, 21, 30 and 60 days after spray (DAA) and plant height and stem diameter at 30 and 60 DAA. The drift of hormonal herbicides caused damage to the growth of pecan and olive trees, decreasing their stem diameter and height, with the herbicide dicamba showing the greatest damage. In addition, doses above 12.5% of both herbicides resulted in phytotoxicity levels greater than 60%, and doses of 50 and 100% were responsible for leaf senescence. Carya K Koch Olea L problems Therefore 2,4D 24D D 2,4 2 4 used follows 0 156 1 56 1.56 3125 3 125 3.125 625 6 25 6.25 120 12 12.0 250 25.0 500 50.0 100 670 (67 ae e ha1 ha ha-1 720 (72 burndown cmhigh cm high CO 15 ha1. 1. 7 14 21 DAA (DAA addition 5 12.5 60% senescence 4D 24 2, 1.5 312 3.12 62 6.2 12. 25. 50. 10 67 (6 ha- 72 (7 31 3.1 6. ( 3.

RESUMO O cultivo de nogueira-pecã (Carya illinoinensis K. Koch) e oliveira (Olea europaea L.) no Sul do Brasil próximo a áreas de pastagens e de cultivo de grãos tem registrado problemas de deriva de herbicidas. Diante disso, o objetivo do trabalho foi avaliar os efeitos fitotóxicos dos herbicidas 2,4-D e dicamba sob o crescimento de mudas de nogueira-pecã e oliveira. Para isso, utilizaram-se 8 subdoses, sendo elas 0; 1,56; 3,125; 6,25; 12,0; 25,0%; 50,0; e 100% das doses recomendadas para dessecação dos herbicidas 2,4-D (670 g e.a ha-1) e dicamba (720 g i.a ha-1). As aplicações foram realizadas em mudas com 80 cm de altura com auxílio de um pulverizador costal pressurizado a CO2 com volume de calda de 150 L ha-1. As variáveis analisadas foram a fitotoxicidade aos 7, 14, 21, 30 e 60 dias após a aplicação (DAA), estatura de plantas e diâmetro de caule aos 30 e 60 DAA. A deriva de herbicidas hormonais causou danos ao crescimento das plantas de nogueira e oliveira, diminuindo o diâmetro de caule e a estatura das mesmas, sendo o herbicida dicamba o responsável pelos maiores danos. Além disso, doses acima de 12,5% de ambos os herbicidas resultaram em fitotoxicidade superior a 60%, sendo as doses de 50 e 100% responsáveis pela senescência de folhas. nogueirapecã pecã Carya K Koch Olea L. disso 2,4D 24D D 2,4 2 4 isso utilizaramse utilizaram se subdoses 0 1,56 156 1 56 3,125 3125 3 125 6,25 625 6 25 12,0 120 12 25,0% 250 50,0 500 100 670 (67 ea ha1 ha ha-1 720 (72 ia i ha1. . CO 15 1. 7 14 21 DAA, DAA , (DAA) mesmas 5 12,5 60% folhas 4D 24 2, 1,5 3,12 312 6,2 62 12, 25,0 50, 10 67 (6 ha- 72 (7 (DAA 1, 3,1 31 6, 25, ( 3,

RESUMO: O arroz daninho (Oryza sativa L.) é a principal planta daninha do arroz cultivado e, devido à similaridade genética com a cultura, são poucas as alternativas de controle. Uma possibilidade são os sistemas de cultivo, em razão da influência na emergência e sobrevivência da espécie no banco de sementes do solo. Diante disso, o trabalho objetivou avaliar a longevidade e a distribuição das sementes de arroz daninho no perfil do solo, após 22 anos de cultivo, sob diferentes sistemas. Os tratamentos foram arranjados em esquema fatorial, em que o fator A foi composto por três sistemas de cultivo, realizados consecutivamente durante 22 anos, sendo esses: semeadura direta (SD), sistema convencional (SC) e pré-germinado (PG); e, o fator B composto por quatro profundidades de amostragem: 0-2, 2-5, 5-10 e 10-20 cm. As variáveis avaliadas foram: o número de sementes íntegras e deterioradas m-2; e, a porcentagem de viabilidade. Não foi verificado efeito dos sistemas até 5 cm, mas a 5-10 cm SC e PG mostraram maior quantidade de sementes, e PG a 10-20 cm. A SD proporcionou diminuição de sementes íntegras conforme aumentou a profundidade de amostragem, enquanto o sistema PG elimina menos sementes do banco de sementes do solo. Os sistemas SC e PG distribuem sementes viáveis no perfil do solo de 0 a 20 cm de profundidade. Após 22 anos, nos três sistemas de cultivo há sementes de arroz daninho viáveis até 10 cm de profundidade, sendo igual a quantidade de sementes viáveis até cinco centímetros de profundidade.

ABSTRACT: Weedy rice (Oryza sativa L.) is the most problematic weed in rice fields due to the few control management alternatives to control it, because of the genetic similarity with the crop. Different cropping systems (regarding soil preparation before sowing) have been used as options to control the persistence and emergence of the weed seedbank. Therefore, the objective of this study was to evaluate the longevity and vertical distribution of weedy rice seeds in the soil seedbank after 22 years of different rice cropping systems. Data was analyzed as a two-way factorial, with cropping systems carried out for 22 years [no-tillage (NT), conventional tillage (CT), wet direct-seeded (WDS)] as one factor and sampling depth (0-2, 2-5, 5-10 and 10-20 cm) as the other factor. The number of whole and deteriorated seeds per m-2 were assessed, as well as the viability (%). No effect between the systems were detected up to 5 cm, however at 5-10 cm CT and WDS showed higher amount of seeds, and WDS at 10-20 cm. As the sampling depth increased, NT showed fewer amount of seeds, while less reduction of the soil seedbank was observed in WDS. CT and WDS spread viable seeds in the soil profile from 0 to 20 cm depth. After 22 years there are viable weedy rice seeds up to 10 cm of depth in the three cropping systems and there is no difference among them up to 5 cm of depth, demonstrating the serious problem of the seedbank for this species.

Resumo O objetivo deste trabalho foi avaliar a seletividade de herbicidas pré e pós-emergentes e a sua eficiência no controle de plantas daninhas, bem como o crescimento e a qualidade de hastes florais, na cultura do gladíolo (Gladiolus x grandiflorus), em duas épocas de cultivo. Os experimentos foram conduzidos a campo, onde os gladíolos plantados receberam a aplicação de herbicidas pré e pós-emergentes, com e sem controle mecânico das plantas daninhas. Aos 7, 14, 21 e 28 dias após a emergência (DAE), avaliaram-se o controle de monocotiledôneas e eudicotiledôneas, além da fitotoxicidade no gladíolo. Aos 28 DAE, também foi avaliada a massa seca da parte aérea das plantas daninhas e dos gladíolos. Os herbicidas pré-emergentes s-metolacloro e diuron e o pós-emergente haloxifope-p-metílico são seletivos ao gladíolo, em ambas as épocas de cultivo, o que possibilita a produção de hastes florais com qualidade comercial. Os herbicidas s-metolacloro e haloxifope-p-metílico também promovem controle eficiente de monocotiledôneas independentemente da época de cultivo. Embora, quando aplicados, saflufenacil e 2,4-D causem fitotoxicidade na fase vegetativa do gladíolo, não afetam a produção de hastes florais e controlam satisfatoriamente as eudicotiledôneas no segundo cultivo. pósemergentes pós emergentes Gladiolus grandiflorus, grandiflorus , grandiflorus) cultivo campo pósemergentes, emergentes, 7 14 2 DAE (DAE) avaliaramse avaliaram se préemergentes smetolacloro s metolacloro pósemergente emergente haloxifopepmetílico haloxifope p metílico comercial Embora aplicados 2,4D 24D D 2,4 4 1 (DAE 4D 24 2,

Abstract The objective of this work was to evaluate the selectivity of pre- and post-emergent herbicides and their efficiency in weed control, as well as the growth and quality of floral stems, in a gladiolus (Gladiolus x grandiflorus) crop in two growing seasons. The experiments were carried out in the field, where the planted gladiolus received the application of pre- and post-emergent herbicides, with and without mechanical weed control. At 7, 14, 21, and 28 days after emergence (DAE), monocotyledon and eudicotyledon control and phytotoxicity to gladiolus plants were evaluated. At 28 DAE, the shoot dry matter of weeds and gladiolus plants was also evaluated. The s-metolachlor and diuron pre-emergent herbicides and the haloxyfop-p-methyl post-emergent herbicide are selective to gladiolus plants in both seasons, which allows of the production of floral stems with commercial quality. The s-metolachlor and haloxyfop-p-methyl herbicides also promote an efficient control of monocotyledons regardless of the growing season. Although, when applied, saflufenacil and 2,4-D cause phytotoxicity in the vegetative phase of gladiolus, they do not affect the production of floral stems and control satisfactorily eudicotyledons in the second season. pre postemergent post emergent Gladiolus grandiflorus seasons field 7 14 21 2 DAE , (DAE) evaluated smetolachlor s metolachlor preemergent haloxyfoppmethyl haloxyfop p methyl season Although applied 2,4D 24D D 2,4 4 1 (DAE 4D 24 2,

ABSTRACT The use of auxin mimics herbicides in agriculture is widespread in a great diversity of crops. The indiscriminate use of herbicides can cause adverse effects in the plants. Among the plant species that stand out for being highly competitive and resistant to biotic and abiotic stresses, it is the brazilian peppertree (Schinus terebinthifolius Raddi.). The objective of this work was to evaluate the phytotoxic and photosynthetic alteration effects of different rates simulating the drift of the herbicides 2,4-D and Dicamba in brazilian peppertree seedlings. The experiment was carried out in a completely randomized design with four replications. The treatments were arranged in 2 x 8 factorial design (herbicide x doses). The factor herbicide consisted the herbicides 2,4-D and Dicamba, and, the factor doses eight percentages of the herbicide applied. Phytotoxicity and alteration of photosynthetic and fluorescence of chlorophyll a parameters were evaluated. Increased rate of the 2,4-D and Dicamba cause phytotoxicity to the plants, whose Dicamba promotes greater injuries. Dicamba was the herbicide that caused the greatest damage to the photosynthetic apparatus on brazilian peppertree plants, while for 2,4-D the plants showed higher recovery potential after herbicidal exposure.

RESUMEN La eficiencia de absorción, translocación y control satisfactorio de malezas pueden ser afectados por el lugar de aplicación del herbicida. Sin embargo, durante la recolección de cultivos previos a la soya, el corte realizado por la cosechadora en la yerba carnicera dificulta el manejo de cultivos en pre-siembra al limitar el área foliar de absorción. Se realizaron experimentos para evaluar la eficiencia del control y el potencial de translocación de saflufenacil en plantas de yerba carnicera en diferentes condiciones. El primer experimento se organizó en esquema factorial 2x10. El factor A corresponde a la integridad de la hoja y el factor B corresponde a los diferentes niveles de daño y aplicación de saflufenacil. El control de Conyza se evaluó a los 7, 14 y 21 días después del tratamiento herbicida (DAT), y el peso seco a los 21 DAT. El experimento II consistió en aplicar saflufenacil a diferentes estructuras de Conyza, donde se evaluó el porcentaje de área necrótica a 1, 3, 5 y 7 DAT. El control de Conyza obtenido fue superior al 75% en todos tratamientos usando saflufenacil, con mayor control en plantas previamente defoliadas. La aplicación de saflufenacil en plantas de 10 y 20 cm fue eficaz en todos los tratamientos. Además, saflufenacil aplicado en el tallo viejo mostró un área necrótica mayor, mientras la aplicación en el sitio del corte generó como resultado un área menos necrótica. La translocación de saflufenacil se da através del xilema y el tallo demostrando ser el elemento a través del cual se da la absorción del herbicida.

ABSTRACT Efficient herbicide absorption and translocation, and satisfactory weed control can be affected by the site of herbicide application. However, during harvesting of crops of previous soybean sowing, the cutting process made by harvesters on the fleabane may generate a difficult management in pre-sowing of the crop by limiting the leaf area of the absorption of the herbicide. Experiments were conducted to evaluate the control efficiency and translocation potential of saflufenacil in fleabane plants with different leaf and stem conditions. Experiment I was arranged in a 2x10 factorial scheme, with factor A corresponding to leaf integrity, and factor B corresponding to different levels of injury and saflufenacil application. Weed control was evaluated at 7, 14, and 21 days after herbicide treatment (DAT), and dry matter was evaluated at 21 DAT. Experiment II consisted of applying saflufenacil to different fleabane structures, where the percentage of necrotic area was evaluated at 1, 3, 5, and 7 DAT. Fleabane control was higher than 75% in all treatments with saflufenacil application, with greater control in plants previously defoliated. Saflufenacil application on 10 and 20 cm hairy fleabane plants was also efficient in all treatments. Saflufenacil application in old stem showed a larger necrotic area, while application in the site of the cutting resulted in a lower necrotic area. The main pathway for translocation of saflufenacil is via xylem and the stem proved to be the absorption element of the herbicide when leaf area is limited.

Resumo: O objetivo deste trabalho foi caracterizar o crescimento e o desenvolvimento da buva (Conyza bonariensis) em razão do acúmulo térmico e do fotoperíodo, em diferentes épocas de semeadura, e propor uma escala para representar os principais estádios de desenvolvimento das plantas. O experimento foi realizado com dez repetições, no período de cultivo 2011/2012. As datas de semeaduras foram: 31/05/2011, 04/07/2011, 03/08/2011, 09/09/2011 e 07/11/2011. A altura de planta (cm) e a fenologia foram avaliadas semanalmente. A duração dos diferentes estádios (dias) e a soma térmica acumulada (°C dia) foram determinadas. A regressão linear mostrou que a altura de plantas relacionou-se à soma térmica acumulada. Independentemente da data de semeadura, a fase vegetativa teve maior duração (em dias e em ºC dia) do que a fase reprodutiva. A semeadura em 07/11/2011 promoveu o encurtamento da fase vegetativa, e o estádio roseta não ocorreu. Houve indução do florescimento em fotoperíodo entre 12,5 e 13,5 horas de luz, independentemente da época de semeadura. Observou-se crescimento mais lento na condição de menor temperatura, em que as plantas acumularam 30,9 e 16,3 °C dia por centímetro de altura, nas semeaduras em 31/05/2011 e 07/11/2011, respectivamente. A escala fenológica prevê adequadamente as fases de desenvolvimento da buva.

Abstract: The objective of this work was to characterize the growth and development of hairy fleabane (Conyza bonariensis) according to thermal accumulation and photoperiod, at different sowing times, and to propose a scale representing the main plant development stages. The experiment was carried out with ten replicates in the 2011/2012 growing season. The sowing dates were: 05/31/2011, 07/04/2011, 08/03/2011, 09/09/2011, and 11/07/2011. Plant height (cm) and phenology were evaluated weekly. The duration of the different stages (days) and thermal time accumulation (°C day) were determined. The linear regression analysis showed that plant height was related to thermal time accumulation. Regardless of the sowing date, the vegetative stage had a longer duration (in days and in ºC day) than the reproductive stage. Sowing on 11/07/2011 promoted the shortening of the vegetative stage, and the rosette stage did not occur. Flowering was induced in the photoperiod between 12.5 and 13.5 hours of light, regardless of the sowing date. Slow growth was observed at lower temperature conditions, when plants accumulated 30.9 and 16.3°C day per centimeter of height for the 05/31/2011 and 11/07/2011 sowing dates, respectively. The phenology scale adequately predicts the development stages of hairy fleabane.

RESUMO: O objetivo deste trabalho foi avaliar a interação entre herbicidas associados ao saflufenacil para o controle de capim-arroz e a determinação do efeito dos herbicidas sobre os parâmetros fotossintéticos e de fluorescência de clorofila. O experimento foi conduzido em casa de vegetação em esquema fatorial 2x8, cujo fator A testou os biótipos resistente e suscetível; e o fator B os herbicidas: saflufenacil (70 g i.a. ha-1), clomazone (180 g i.a. ha-1), imazapyr+imazapic (73,5+24,5 g i.a. ha-1), cyhalofop (360 g i.a. ha-1), as associações desses com saflufenacil, e testemunha sem tratamento. Foi avaliado o controle aos 7, 14, 21 e 28 dias após a aplicação dos herbicidas (DAA), massa seca da parte aérea aos 28 DAA, avaliação de parâmetros fotossintéticos com analisador de gás infravermelho (IRGA) e emissão de fluorescência da clorofila a 24 e 48 horas após aplicação dos tratamentos, respectivamente, e interação dos herbicidas. A associação de saflufenacil com herbicidas testados na maior parte não modificou a resposta dos herbicidas para o controle de capim-arroz em ambos os biótipos. O biótipo resistente apresentou menor efeito negativo nos processos de fluorescência de clorofila e parâmetros de fotossíntese na associação de herbicidas com saflufenacil. O herbicida cyhalofop associado ao saflufenacil demonstra ser eficiente para o controle de capim-arroz suscetível e resistente a ALS.

ABSTRACT: The objectives of this research were to evaluate the interaction between herbicides mixed with saflufenacil for the control of barnyardgrass and to determine the effect on photosynthetic and chlorophyll fluorescence parameters. The experiment was conducted in a greenhouse in a 2x8 factorial scheme, whose factor A tested resistant and susceptible biotypes; and factor B the herbicides: saflufenacil (70 g a.i. ha-1), clomazone (180 g a.i. ha-1), imazapyr + imazapic (73.5 + 24.5 g a.i. ha-1), and cyhalofop (360 g a.i. ha-1), the mixtures of these herbicides with saflufenacil, and control without treatment. Weed control was assessed 7, 14, 21 and 28 days after herbicide application (DAA), as well as shoot dry matter at 28 DAA, photosynthetic parameters using infrared gas analyzer (IRGA), and emission of chlorophyll a fluorescence after 24 and 28 hours of application of treatments, respectively, and interaction of herbicides. Combination of saflufenacil with the herbicides tested in general did not change the response of both barnyardgrass biotypes to the herbicides used. The resistant biotype showed a lower negative effect on chlorophyll fluorescence and photosynthesis parameters in the combination of herbicides with saflufenacil. The herbicide cyhalofop was effective for the control of ALS-susceptible and resistant barnyardgrass.

ABSTRACT The residue of imidazolinone herbicides in soil can be detrimental to soybean cultivation in rotation with Clearfield® rice. Thus, this research aimed to evaluate the ryegrass phytoremediation capacity on the imazapyr+imazapic residue in the soil in two soil moisture conditions in the off-season, and the effect on soybean growth in the next growing season. Two experiments were conducted between 2016 and 2017 in Santa Maria, Rio Grande do Sul state, Brazil. It was used the randomized block design in a 3 × 2 factorial. The first factor being the residue in the soil of 0, 210 and 420 g c.p.·ha–1 of the formulated mixture of the herbicides imazapyr+imazapic(525 + 175 g a.i.·kg–1) applied to rice in the 2015/2016 growing season, and the second factor being the presence or absence of ryegrass in the off-season. One experiment was conducted under soil moisture above 70% of field capacity in the off-season, and the other under ambient condition of soil moisture. The soil residue of the application of 420 g c.p.·ha–1 of the imazapyr+imazapic herbicides performed129 days before planting caused phytotoxicity and reduced dry matter of ryegrass under high soil moisture condition in the off-season in irrigated rice areas. Soybean, when planted 359 days after application, has its initial root and shoot growth affected by the residue of 210 and 420 g c.p.·ha–1 rates in high soil moisture condition in the off-season, regardless of ryegrass cultivation during the same period. However, grain yield is not affected.

RESUMEN El manejo de raigrás es difícil debido a la ocurrencia de biotipos resistentes a diversos herbicidas con diferentes mecanismos de acción. Dado que la mezcla de herbicidas y sus rotaciones son una alternativa importante para el manejo de malezas resistentes, el objetivo de este trabajo fue evaluar la interacción de las dosis de los herbicidas glufosinato y atrazina para el control de raigrás y la calidad de sus semillas expuestas a su asociación. Se realizaron tres experimentos usando diseño factorial en condiciones de campo, laboratorio e invernadero. Dos factores (A y B) fueron evaluados en cada experimento, donde el factor A y B representaron las dosis de glufosinato y de atrazina, respectivamente. El control de raigrás fue evaluado en el experimento de campo, mientas que el porcentaje de germinación y el Índice de Velocidad de Emergencia (IVE) se determinaron en laboratorio e invernadero, respectivamente. Los datos fueron sometidos a análisis de la varianza (P≤0,05) y los resultados significativos fueron analizados a través de gráficos de superficie de respuesta. Para los datos de control, el efecto de las interacciones fue analizado por medio del método Colby; el glufosinato proporcionó un eficiente control de raigrás, pero su asociación con atrazina reduce su eficacia, siendo caracterizando como antagonismo entre moléculas. La aplicación del herbicida glufosinato, independiente de la presencia de atrazina, redujo la calidad de las semillas de raigrás en la fase de post-floración.

ABSTRACT Ryegrass management has been difficult by the occurrence of resistant biotypes to several herbicides with different action mechanisms. Since herbicides mixes and rotations are an important alternative for resistant weed management, the objective of this work was to evaluate the interaction of the dose of the herbicides glufosinate and atrazine on ryegrass control and its seeds’ quality exposed to their association. For this study, three experiments were carried out using factorial design in field, laboratory, and greenhouse conditions. Two factors (A and B) were evaluated in each experiment, where factor A and B represented the doses of glufosinate and atrazine, respectively. Ryegrass control was evaluated in field experiment, while germination percentage and Emergence Speed Index (ESI), were obtained in laboratory and greenhouse analyses, respectively. The data were submitted to variance analysis (P≤0.05) and the significant results were analyzed through response surface graphs. For ryegrass control data, the effect of the interaction was analyzed by the Colby method; glufosinate provides efficient ryegrass control, but its association with atrazine reduces the efficiency, being characterized as an antagonism between molecules. Glufosinate herbicide application, independent of atrazine presence, reduced the ryegrass seeds quality at the post-flowering stage.

Resumo: Para proporcionar maior seletividade do herbicida clomazone à cultura do arroz, pode-se utilizar o protetor dietholate em conjunto com outros tratamentos de sementes (ST), o que possibilita o uso de doses maiores do herbicida. O objetivo do trabalho foi avaliar a interação entre o tratamento de sementes que utilizam fungicidas e inseticidas e o protetor dietholate em arroz irrigado. Foram realizados três experimentos, sendo que o primeiro foi conduzido em laboratório, em delineamento experimental inteiramente casualizado com quatro repetições. Neste caso, testou-se diferentes ST e intervalo em dias entre o tratamento de sementes e a semeadura. O segundo e o terceiro experimentos foram realizados em campo, seguindo um delineamento experimental de blocos casualizados com quatro repetições. No experimento dois, foram testados diferentes fungicidas nos ST com ou sem a adição de dietholate; enquanto no experimento três avaliou-se o efeito dos ST com fungicidas e dietholate, quando aplicados juntamente com clomazone. Os resultados evidenciaram que a associação carboxin + thiram + dietholate reduziu a germinação, o vigor de sementes e a matéria seca da parte aérea de plantas de arroz irrigado. O aumento no tempo entre o ST e a semeadura reduziu a germinação de arroz. A associação de fungicidas em combinação com dietholate no ST pode ter ação antagônica e interferir no estabelecimento da cultura.

Abstract: The plant safener dietholate can be used for seed treatments (ST) to improve the selectivity of clomazone in rice cultures, thus allowing the application of higher dosages of this herbicide. The objective of this research was to evaluate the interaction between seed fungicide-insecticide treatments with and the plant safener dietholate in irrigated rice. Three experiments were carried out, and the first of them was conducted in a laboratory, following a completely randomized experimental design with four replications. Different ST and treatment-to-sowing intervals were evaluated. The second and third experiments were performed in field conditions, in a completely randomized block design with four replications. In experiment two, seeds were treated with different fungicides, in association or not with dietholate; while in experiment three, the effect of the ST with fungicides and dietholate with clomazone application were assessed. The results evidenced that the association between carboxin + thiram + dietholate reduced seed germination, vigor, and the dry mass of shoot of rice plants. The longer it takes between ST and sowing, the more rice seed germination is negatively affected. The association between fungicides and dietholate may have been antagonistic, and thus interfered with the culture growth potential.

Resumo: O objetivo deste trabalho foi modelar a competição de arroz-daninho (Oryza sativa) e capim-arroz (Echinochloa spp.) com o arroz irrigado por inundação e introduzi-la como um submodelo no modelo SimulArroz. A competição das duas ervas daninhas com o arroz irrigado foi modelada com o uso da equação da hipérbole retangular. Os coeficientes “i” e “a” da hipérbole retangular referentes a cada erva foram obtidos na literatura e em experimentos de campo conduzidos no Rio Grande do Sul. No SimulArroz, a perda de produtividade foi aplicada para penalizar a produtividade nos três níveis tecnológicos (alto, médio e baixo) para maturidade fisiológica. Para o arroz-daninho, os valores do coeficiente imédio, para os níveis tecnológicos alto, médio e baixo, foram 1,04, 1,50 e 3,57, respectivamente, e, para o capim-arroz, foram 4,70, 10,49 e 15,51, respectivamente. O coeficiente “a” foi 100 para o arroz-daninho, e o amédio, para o capim-arroz, foi 101,63, 104,92, 96,88 para os níveis tecnológicos alto, médio e baixo, respectivamente. A abordagem de perda de produtividade foi adequada para modelar a competição de arroz-daninho e capim-arroz com o arroz irrigado. O submodelo de perda de produtividade pela competição de arroz-daninho e capim-arroz com o arroz irrigado melhora a capacidade preditiva do modelo SimulArroz.

Abstract: The objective of this work was to model weedy rice (Oryza sativa) and barnyard grass (Echinochloa spp.) competition with flood-irrigated rice, introducing it as a submodule into the SimulArroz model. The competition of both weeds with irrigated rice was modeled using the rectangular hyperbola equation. The “i” and “a” coefficients of the rectangular hyperbola for each of these weeds were obtained from the literature and from field experiments carried out in the state of Rio Grande do Sul, Brazil. In SimulArroz, yield loss was applied to penalize yield in all three technological levels (high, medium, and low) of physiological maturity. For weedy rice, the coefficient values of imean for the high, medium, and low technological levels were 1.04, 1.50, and 3.57 respectively, and, for barnyard grass, 4.70, 10.49, and 15.51 respectively. Coefficient “a” was 100 for weedy rice, and amean values for barnyard grass were 101.63, 104.92, and 96.88 for the high, medium, and low levels, respectively. The yield loss approach was suitable to model the competition of weedy rice and barnyard grass with irrigated rice. The submodule yield loss caused by the competition of weedy rice and barnyard grass with irrigated rice improves the predictive capacity of the SimulArroz model.

O objetivo deste trabalho foi determinar a taxa de acúmulo de matéria seca e a duração do período de enchimento de grãos de cultivares de arroz irrigado com diferentes grupos de maturação e épocas de semeadura. Para a determinação da taxa e duração do período de enchimento de grãos, a partir do florescimento foram realizadas amostragens por cultivar. Foi ajustada a relação entre dias após florescimento e peso de grão. Os resultados indicaram que a antecipação da época de semeadura promoveu um atraso no período de ocorrência da maior taxa de enchimento de grãos durante o ciclo de desenvolvimento. As cultivares de ciclo tardio tiveram uma maior duração do período de enchimento de grãos (31 dias), em relação as cultivares de ciclo precoce e médio. As cultivares com maiores taxas de enchimento de grãos apresentaram maior peso em R9, menor número de grãos por panícula e menor duração do período de enchimento de grãos. Houve variação na taxa de enchimento de grãos e na duração do período de enchimento de grãos de acordo com o grupo de maturação, em que as cultivares de ciclo tardio apresentaram menor taxa e maior duração no período de enchimento de grão.

The objective of this work was to determine the rate of accumulation of dry matter and the duration of the grain filling period of irrigated rice cultivars with different maturation groups and sowing dates. To determinate the rate and duration of the grain filling period, samples per cultivar were taken. The relation was adjusted between days after flowering and grain weight. The results indicated that the anticipation of the sowing date promoted a delay in the period of occurrence of the highest rate of grain filling. The late cycle cultivars had a longer duration of the grain filling period (31 days), in relation to the cultivars of early and medium cycle. Then, the cultivars with higher grain filling rates showed higher grain weight in R9, lower number of grain per panicle and shorter grain filling period. Thus, it was possible to conclude that there was a variation in the grain filling rate and the grain filling period of irrigated rice cultivars with different maturation groups, which in the late cycle cultivars had a lower rate and a longer duration in the grain filling period. Then, it was identified that the grain weight is associated with the grain filling rate.